Ultrasonic medical imaging systems are widely used because of their versatility and relatively low cost. The diagnostic capabilities of these devices has increased over the past few years with advances in computer hardware and software. Developments in transducer technology have not been nearly as dramatic, so the transducer now presents a barrier to further advances in diagnostic ultrasound. We propose a new technique for manufacturing ultrasonic transducers, based on physical vapor deposition (PVD) and other standard techniques used in the semiconductor industry. This process will allow acoustic elements with different frequency characteristics to coexist on a single transducer array. A multi- frequency transducer is ideally suited for harmonic imaging, a powerful new high resolution imaging modality where the transducer receives ultrasonic echoes at double the frequency of transmission. Our transducer would increase the clinical potential and market penetration of this imaging modality. In Phase I of this project, a prototype will be constructed to demonstrate the feasibility of a multi-frequency array. During Phase ll, we will build a prototype clinical transducer array and perform an initial validation study. The end result of this work will be a new generation ultrasound transducer, which will dramatically enhance the diagnostic capabilities of ultrasonic imaging. PROPOSED COMMERCIAL APPLICATIONS: The medical ultrasound transducer marketplace is responsible for $300 million of worldwide revenues each year and is continuing to grow rapidly. Ultrasound is already a vital diagnostic tool in the areas of cardiology, OB/GYN, and oncology. Creare's technology promises to increase the performance of ultrasound in current applications and open the door to powerful new high-resolution modalities such as harmonic imaging.